Research Document - 2016/058
The Status of Yellowtail Flounder in NAFO Division 4T to 2015
By T. Surette and D.P. Swain
Abstract
Yellowtail flounder (Limanda ferruginea) landings in NAFO 4T peaked in 1986-1987 (400 t) and in 1997 (819 t) and declined from 305 t in 1999 to 102 t in 2015. A TAC of 300 t has been in place since 2000. Yellowtail are mainly exploited in a bait fishery located in the Magdalen Islands since 1995 and almost exclusively so since 2004. Abundance indices from a research survey have been stable since the mid-eighties. However, corresponding biomass indices have decreased due to a shift in modal size from 29 cm in the early 1970s to 22 cm in recent years. Size-at-maturity in both males and females has declined from 23-24 cm in the in the early 1970s to 12-13 cm in recent years. Annual mortality of small fish has decreased from 53% to 16-22% while that of larger fish has increased from 22% to 86% from the middle to late eighties to the present. While spawning stock biomass has increased, the proportion of older (7+ years) fish has declined from 40% in 1985-1990 to less that 0.5% since 2013. Fishing mortality is estimated to be very low and there were no perceived differences in stock projections over the next five years at catch levels of 0 t, 100 t, and 300 t annually. A limit reference point (Blim = 1.06 kg/tow) was derived from the commercial sized (≥ 25 cm) biomass index from the research vessel survey. The abundance index in 2015 was at 61% of Blim.
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